Plasma display panel and method of manufacturing the same

ABSTRACT

A plasma display panel (PDP) including a front substrate and a rear substrate facing each other, a partition wall interposed between the front substrate and the rear substrate to define a plurality of unit cells, each unit cell including a main discharge space, an auxiliary discharge space, and a step space, the auxiliary discharge space and the step space being on opposite sides of the main discharge space along a stepped sidewall of the partition wall, pairs of scanning and sustain electrodes arranged adjacent the auxiliary discharge spaces and to the step spaces, respectively, address electrodes extending to cross the scanning electrodes at a location adjacent to the auxiliary discharge spaces, a phosphor layer formed at least in the main discharge spaces, and discharge gas filling the unit cell.

BACKGROUND

1. Field

Embodiments relate to a plasma display panel (PDP) and method ofmanufacturing the same and, more particularly, to a PDP in which anaddress discharge path is shortened so that low-voltage addressing ispossible, and having symmetric discharge in each unit cell realizing apredetermined image, thereby improving overall displaying quality.

2. Description of the Related Art

In a PDP, a plurality of discharge cells arranged in a matrix form isinterposed between upper and lower substrates facing each other.Discharge electrodes including pairs of scanning electrodes and sustainelectrodes, which cause mutual discharge, and a plurality of addresselectrodes are disposed on the substrates. An appropriate discharge gasis injected between the substrates, a predetermined discharge pulse isapplied between discharge electrodes, fluorescent substances appliedwithin the plurality of discharge cells are excited, and a predeterminedimage is realized using generated visible light.

In such a PDP, one image frame is divided into a plurality of sub-fieldseach having different light emitting frequency and is time-sharedoperated to realize a grey scale image. Each sub-field includes a resetperiod to uniformly generate discharge, an address period to select theplurality of discharge cells, and a sustain period to realize the greyscale according to discharge frequency. During the address period,auxiliary discharge occurs between the address electrodes and thescanning electrodes so that wall charge results in selected dischargecells, and thus, a condition suitable for the auxiliary discharge iscreated.

In general, a high voltage, i.e., a voltage higher than a sustaindischarge, is required during the address period for selecting adischarge cell to be displayed. Moreover, as the PDP rapidly develops toa full high definition (HD) level, the number of the discharge cellsincreases in geometrical proportion, increasing power consumption by acircuit unit in proportion to the number of address electrodes allocatedto each discharge cell. In addition, in a so-called high Xenon (Xe)display in which a partial pressure of Xe is increased within thedischarge gas injected into the panel, a light-emitting efficiency isincreased. A relatively high address voltage, however, is required fordischarge initiation in such a high Xe display, further increasing powerconsumption.

SUMMARY

Embodiments are therefore directed to a PDP and method of manufacturingthe same, which substantially overcome one or more of the problems dueto the limitations and disadvantages of the related art.

It is therefore a feature of an embodiment to provide a highly efficientPDP that enables address driving with a low voltage.

It is therefore another feature of an embodiment to provide a PDP inwhich light-emitting efficiency is remarkably improved by realizing ahigh xenon (Xe) display.

It is therefore another feature of an embodiment to provide ahigh-quality PDP in which symmetric discharge is generated in each unitcell where a predetermined image is realized, and thus, an overalldisplay quality of the PDP is improved.

It is therefore another feature of an embodiment to provide a PDP inwhich consumption of reactive power, which does not contribute to lightemitting luminance, may be reduced and discharge intervention betweenneighboring cells is prevented.

At least one of the above and other features and advantages may berealized by providing PDP including a front substrate and a rearsubstrate facing each other, a partition wall interposed between thefront substrate and the rear substrate to define a plurality of unitcells, each unit cell including a main discharge space, an auxiliarydischarge space, and a step space, the auxiliary discharge space and thestep space being on opposite sides of the main discharge spaces along astepped sidewall of the partition wall, pairs of scanning and sustainelectrodes arranged adjacent the auxiliary discharge spaces and to thestep spaces, respectively, address electrodes extending to cross thescanning electrodes at a location adjacent to the auxiliary dischargespaces, a phosphor layer formed at least in the main discharge spaces,and discharge gas filling the unit cell.

The auxiliary discharge spaces and the step spaces may be connected tothe main discharge spaces and form the unit cells with the maindischarge spaces.

The auxiliary discharge space and the step space may be symmetrical toeach other with respect to the main discharge space.

The sustain electrodes and the scanning electrodes may have an electrodearrangement of X-X-Y-Y, the sustain electrodes being X and the scanningelectrodes being Y, so that the sustain electrodes and the scanningelectrodes neighbor each other in adjacent cells.

The stepped sidewall of the partition wall may include a base part and aprojection part that projects from a center of the base part, the basepart being wider than the projection part to define a step form on eachside of the projection part.

The width of the base part of the partition wall may be substantiallythe same as a distance between an outer edge of one bus electrode to anouter edge of an adjacent bus electrode in an adjacent unit cell, theouter edge of each bus electrode facing away from its correspondingadjacent bus electrode.

The base parts and respective bus lines of the scanning electrodes mayat least partially cover each other and may be arranged to overlap eachother.

The base part and the bus lines of the scanning electrodes may overlapeach other at end parts adjacent to the main discharge space.

The PDP may further include an electron emission material layer on a topsurface of the base part in the auxiliary discharge space.

The electron emission material layer may be continuously formed alongthe top surface of the base part in the auxiliary discharge space and aside of the projection part in the auxiliary discharge space.

The electron emission material layer may be formed on the main dischargespace as well as along the top surface of the base part in the auxiliarydischarge space and a side of the projection part in the auxiliarydischarge space.

A side of the base part may concave away from the main discharge space.

A side of the base part may convex toward the main discharge space.

The phosphor layer may not be formed on the top surface of the base partin the auxiliary discharge space.

The phosphor layer may be extended to the step spaces on one side of themain discharge space.

The phosphor layer may be extended to the step spaces and the auxiliarydischarge spaces on both sides of the main discharge spaces.

The phosphor layer may be formed to have a maximum thickness in the maindischarge spaces.

The maximum thickness may be substantially the same as a height of thestepped surface of the partition wall.

A high xenon (Xe) gas may be used as the discharge gas.

At least one of the above and other features and advantages may berealized by providing a method of manufacturing a PDP, method includinginterposing a partition wall between opposing front and rear substratesto define a plurality of unit cells including main discharge spaces,auxiliary discharge spaces, and step spaces, the auxiliary dischargespace and the step space being on opposite sides of the main dischargespaces along a stepped surface of the partition wall, disposing pairs ofsustain electrodes and scanning electrodes on the front substrates, thesustain electrodes being arranged close to the auxiliary spaces and thescanning electrodes being arranged close to the step spaces, disposing aplurality of address electrodes on the rear substrates, the addresselectrodes extending to cross the scanning electrodes at a location atleast adjacent to the auxiliary discharge spaces, forming a phosphorlayer at least in the main spaces, and filling discharge gas in the maindischarge spaces, auxiliary discharge spaces, and the step spaces.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages will become more apparent tothose of ordinary skill in the art by describing in detail exemplaryembodiments with reference to the attached drawings, in which:

FIG. 1 illustrates an exploded perspective view of a PDP according to anembodiment;

FIG. 2 illustrates a cross-sectional view of the PDP illustrated in FIG.1, taken along line II-II of FIG. 1;

FIG. 3 illustrates a plan view of an arrangement of scanning electrodesand sustain electrodes of FIG. 1;

FIG. 4 illustrates an exploded perspective view of a main part of a PDPextracted from the PDP of FIG. 1;

FIG. 5 illustrates an exploded perspective view between a PDP accordingto another embodiment;

FIG. 6 illustrates a cross-sectional view of the PDP of FIG. 5, takenalong line VI-VI of FIG. 5;

FIG. 7 illustrates an exploded perspective view of a PDP according toanother embodiment;

FIG. 8 illustrates a cross-sectional view of the PDP of FIG. 7, takenalong line VIII-VIII of FIG. 7;

FIG. 9 illustrates a cross-sectional view of a modified PDP of FIG. 8;

FIG. 10 illustrates a cross-sectional view of another modified PDP ofFIG. 8;

FIG. 11 illustrates an exploded perspective view of a PDP according toanother embodiment;

FIG. 12 illustrates a plan view of a partition wall illustrated in FIG.11; and

FIG. 13 illustrates a plan view of a modified partition wall of FIG. 12.

DETAILED DESCRIPTION

Korean Patent Application No. 10-2008-0078719, filed on Aug. 12, 2008,in the Korean Intellectual Property Office, and entitled: “PlasmaDisplay Panel,” is incorporated by reference herein in its entirety.

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may beexaggerated for clarity of illustration. It will also be understood thatwhen a layer or element is referred to as being “on” another layer orsubstrate, it can be directly on the other layer or substrate, orintervening layers may also be present. Further, it will be understoodthat when a layer is referred to as being “under” another layer, it canbe directly under, and one or more intervening layers may also bepresent. In addition, it will also be understood that when a layer isreferred to as being “between” two layers, it can be the only layerbetween the two layers, or one or more intervening layers may also bepresent. Like reference numerals refer to like elements throughout.

FIG. 1 illustrates an exploded perspective view of a PDP according to anembodiment. FIG. 2 illustrates a cross-sectional view of the PDPillustrated in FIG. 1, taken along line II-II of FIG. 1.

The PDP may include a front substrate 110, a rear substrate 120, and apartition wall 124. The front substrate 110 and the rear substrate 120may be spaced apart and facing each other, and the partition wall 124may partition a space between the front substrate 110 and the rearsubstrate 120 into a plurality of unit cells S. The unit cell Spartitioned by the partition wall 124 may be a minimum light emittingunit for realizing a predetermined display. The unit cell S may includea pair of sustain and scanning electrodes X and Y, arranged to generatemutual display discharge, and an address electrode 122 extending in adirection perpendicular to the pair of sustain and scanning electrodes Xand Y. The unit cell S may form a separate light emitting region fromneighboring unit cells S. The sustain electrode X and scanning electrodeY may include a bus electrode 112X and a transparent electrode 113X anda bus electrode 112Y and a transparent electrode 113Y, respectively. Thebus electrodes 112X and 112Y may function as supply lines of a drivingpower source and may extend across the unit cell S. The transparentelectrodes 113X and 113Y may be formed of optically transparentconductive materials.

The address electrode 122 may be disposed on the rear substrate 120, andmay perform address discharge along with the scanning electrode Y. Here,the address discharge that precedes the display discharge may be denotedas an auxiliary discharge supporting the display discharge byaccumulating priming particles in each unit cell S. The addressdischarge may mainly be generated in an auxiliary discharge space S1defined by the partition wall 124. That is, the address discharge mayoccur at the auxiliary discharge space S1 where the scanning electrode Yand the address electrode 122 cross each other or at least at a positionadjacent to the auxiliary discharge space S1.

A discharge voltage applied between the scanning electrode Y and theaddress electrode 122 may be centralized in the auxiliary dischargespace S1 by a dielectric layer 114, covering the scanning electrodes Y,and the partition wall 124 disposed on the address electrode 122.Therefore, a high electric field sufficient for discharge initiation maybe formed in the auxiliary discharge space S1. The auxiliary dischargespace S1 may not be physically partitioned by other wall structures, butmay extend from a main discharge space SP to form a space, e.g., theunit cell S, with the main discharge space SP.

The priming particles formed in the auxiliary discharge space S1 due tothe address discharge may naturally be diffused to the main dischargespace SP and may participate in the display discharge. The auxiliarydischarge space S1 may be defined by the partition wall 124 that isstepped, and may have a smaller discharge volume than the main dischargespace SP. A step space S2 may be formed on the side of the sustainelectrode X. Thus, the step space S2 may be symmetrical to the auxiliarydischarge space S1 with respect to the main discharge space SP.

The address electrode 122 may be covered by a dielectric layer 121disposed on the rear substrate 120, and the partition wall 124 may beformed on a top surface of the dielectric layer 121 that is evenlyformed. The partition wall 124 may be shaped like a step with a basepart 124 a and a projection part 124 b. The base part 124 a may have awidth Wa, larger than the width of the projection part 124 b, and may beinterposed between the front substrate 110 and the rear substrate 120.The base part 124 a may be on the dielectric layer 121. The projectionpart 124 b may be projected toward the front substrate 110 from a centerof the base part 124 a. The projection part 124 b may be in contact witha protective layer 115.

The dielectric layer 114 and/or a protective layer 115 covering thescanning electrode Y and the base part 124 a disposed on the addresselectrodes 122 may form discharge surfaces facing each other and, thus,may enable address discharge to occur mainly within the auxiliarydischarge space S1. In other words, the electrical field may be mainlycentralized in the auxiliary discharge space S1 by high permittivity ofthe dielectric layer 114 and/or the protective layer 115 covering thescanning electrode Y and the partition wall 124 formed on the addresselectrode 122. Further, opposing discharge with the top surface of thedielectric layer 114 and the bottom surface of the base part 124 a asmain discharge surfaces may be generated in the discharge space S1.

Conventionally, discharge is generated between the scanning electrode Yand the address electrode 122 through a long-distance discharge path,e.g., the height of the unit cell. According to the wall structure ofthe current embodiment in which the base part 124 a with a predeterminedheight is projected toward the scanning electrode Y and extends into theunit cell, a discharge path between the scanning electrode Y and theaddress electrode 122 may, however, be shortened to a size of adischarge gap g.

The discharge gap g may have a distance that is substantially same asthe distance between a bottom surface of the protective layer 115 and anupper surface of the base part 124 a. Therefore, the driving consumptionpower may be reduced because the same amount of priming particles may begenerated by using a lower address voltage. Furthermore, light-emittingefficiency may be improved since more priming particles may be generatedby using the same address voltage used in the prior art. The partitionwall 124 may be formed of a material having permittivity higher than apredetermined value and, thus, a high address electric field in theauxiliary discharge space S1 may be formed through the base part 124 aof the partition wall 124. For example, the partition wall 124 may beformed of a dielectric material including PbO, B₂O₃, SiO₂, and TiO₂.

FIG. 3 illustrates a plan view of an arrangement between the scanningelectrodes Y and the sustain electrodes X.

Referring to FIG. 3, the scanning electrodes Y and the sustainelectrodes X may not be alternatively arranged, e.g., XYXY, but instead,may be arranged such that electrodes of the same kind neighbor eachother in the adjacent unit cells S, e.g., YXXY. More specifically, sincethe scanning electrode Y, the sustain electrode X, the sustain electrodeX, and the scanning electrode Y may be sequentially arranged in thisorder, one sustain electrode X may be arranged to neighbor the sustainelectrode X of the adjacent unit cell S, while one scanning electrode Ymay be arranged to neighbor the scanning electrode Y of the adjacentunit cell S. If the scanning electrode Y, the sustain electrode X, thescanning electrode Y, and the sustain electrode X are alternativelyarranged in this order, the scanning electrode Y and the sustainelectrode X in the adjacent unit cell S may be arranged to neighbor eachother. Thus, mis-discharge, e.g., sustain discharge exceeding theboundary of the unit cell S, may potentially be generated.

In addition, because the scanning electrode Y and the sustain electrodeX neighbor each other according to the alternating arrangement of theelectrodes, a high capacitance value may be formed between the scanningelectrode Y and the sustain electrode X based on various paths. Forexample, since the dielectric layer 114 have a permittivity that ishigher than discharge gas by about 12 times, reactive power consumptionmay be increased and driving efficiency may be decreased. Thus, byarranging the electrodes such that the same kind of electrodes neighborseach other, mis-discharge may be prevented and an improvement of drivingefficiency may be achieved as the result of reduced reactive power.

Because the sustain and scanning electrodes X and Y may be covered bythe dielectric layer 114 to be prevented from being exposed to adischarge environment, the sustain and scanning electrodes X and Y maybe protected from a direct collision with charged particles thatparticipate in the discharge. The dielectric layer 114 may be protectedby being covered by the protective layer 115 formed of, e.g., a MgOfilm. The protective layer 115 may induce secondary electrode emissionand may contribute to activate discharge.

FIG. 4 illustrates an exploded perspective view of a main part of thePDP extracted from the PDP of FIG. 1.

With regard to the structure of the partition wall 124, the width of thebase part 124 a may be related to a discharge area facing the scanningelectrode Y and may also be related to a discharge volume of the wholeunit cell S. For example, when a width of the base part 124 a isadjusted to have the width Wa, the discharge area facing the scanningelectrodes Y may be sufficiently large to have a smooth addressdischarge. Further, an area that the base part 124 a occupies in thedischarge area may be sufficiently small to increase a discharge volume.For example, the width Wa of the base part 124 a may be substantiallythe same as a distance between an outer edge of one bus electrode 112Yfrom an outer edge of an adjacent bus electrode 112Y, i.e., an outeredge of a bus electrode 112Y in one unit cell may face away from anadjacent bus electrode 112Y of an adjacent unit cell. For example, oneend, i.e., an outer edge, of the bus electrode 112Y may be arranged tocorrespond to, e.g., be aligned with, one end of the base part 124 a.The bus electrode 112Y and the base part 124 a may be arranged tooverlap one another at end parts adjacent to the main discharge space.

To secure sufficient discharge area with the scanning electrode Y and tohave appropriate discharge volume, one end of the bus electrode 112Y maybe arranged to correspond to one end of the base part 124 a. Forexample, one end of the bus electrode 112Y may be perpendicular to oneend of the base part 124 a. To facilitate address discharge, the buselectrode 112Y and the base part 124 a may be arranged to overlap oneanother. Also, the width Wa of the base part 124 a may be no more than adistance from one bus electrode, e.g., 112Y, to adjacent bus electrode,e.g., 112Y so that the maximum discharge volume may be secured. Inconsideration of an arrangement error that is generally allowed in amanufacturing process, the width Wa of the base part 124 a, however, maybe designed to be large enough to have a spare margin e. The margin emay be smaller than a half width of the main discharge space SP.

Address discharge centralized in the auxiliary discharge space S1 mayprovide priming particles for ignition of display discharge, instead ofdirectly providing display discharge. When discharge light generatedduring address discharge is inevitably exposed to the outside along withthe display luminescence, blurred luminance noise may be formed aroundactive pixels and may decrease display definition. In the currentembodiment, by using an optically opaque property of the bus electrode112Y, which is generally formed of a metal conductive material, and byarranging the bus electrode 112Y on the base part 124 a in which addressdischarge is centralized, a considerable amount of discharge light and ageneration of luminance noise may be prevented, while improving acontrast property.

In the current embodiment, the auxiliary discharge space S1 formed onthe side of the scanning electrode Y may be used to generate centralizedaddress discharge. The step space S2 may be formed on the side of thesustain electrode X. Thus, the step space S2 may be symmetrical to theauxiliary discharge space S1 with respect to the main discharge spaceSP. Because the unit cell S is symmetrical, display discharge may notlean toward any one of the scanning electrode Y or the sustain electrodeX, but instead, may have symmetrical discharge having the same dischargeintensity. Accordingly, luminance distribution in the unit cell S may besymmetrical in that the luminescent center indicating the highestluminance may generally be a geometrical center of the unit cell S.Therefore, display quality deterioration due to asymmetrical luminancedistribution may be prevented.

A liquid phosphor paste may be applied between the partition wall 124,e.g., main discharge space SP, and the liquid phosphor paste may hardento be a phosphor layer 125. The phosphor layer 125 may interact withultraviolet light generated as a result of the display discharge and maygenerate visible light having each different color. For example,according to a color to be realized, R, G, and B phosphor layers 125 maybe formed in the unit cells S, and thus, each unit cell S may beclassified as R, G, and B sub-pixels. In the structure where the basepart 124 a having width Wa is disposed on both sides of the unit cell S,a groove r may be provided to hold the phosphor paste at the center ofthe unit cell S, and thus, the phosphor layer 125 may be centralized atthe center of the unit cell S. The groove r may have a maximum height,which may be the substantially the same as a height of the base part 124a, at its edge. That is, while applying the phosphor paste, the flowingof the phosphor paste may be obstructed by the base part 124 a arrangedon both sides of the unit cell S, and thus, the phosphor layer 125 maybe centralized at the center of the unit cell S. As the phosphor layer125 having a maximum thickness T centralizes at the center of the unitcell S where ultraviolet rays are centralized by the display dischargeoccurring between the scanning electrode Y and the sustain electrode X,the conversion efficiency of the ultraviolet rays may be increased,resulting light emitting luminance to increase.

As described above, the phosphor layer 125 may be centralized in thegroove r between the base parts 124 a. Embodiments, however, are notlimited thereto, and the phosphor layer 125 may also be formed in otherparts of the unit cell S, i.e., the top surface of the base part 124 aand/or a side surface of the projection part 124 b as illustrated inFIGS. 1, 2, and 4. In particular, an application process in which thephosphor paste may be applied continuously across a row of the unitcells S may be used to form the phosphor layer 125 in other parts of theunit cell S.

Also, discharge gas may be injected into the unit cell S as a source forgenerating ultraviolet rays. Examples of the discharge gas may include amulti gas in which xenon (Xe), krypton (Kr), helium (He), and neon (Ne)are mixed in a fixed volume ratio. In general, a high xenon (Xe) displaypanel, in which a ratio of xenon (Xe) is increased, may have a highlight-emitting efficiency. Because the high xenon (Xe) display panel,however, requires high initiation voltage, which further requiresincreased driving power consumption and redesign of a circuit toaccommodate increased electric power, actual and broad applications ofthe high xenon (Xe) display panel may be limited. According to thepresent embodiment in which a high electric field suitable for addressdischarge is formed through the base part 124 a of the partition wall124, however, the sufficient priming particles for discharge ignitionmay be secured so that a high xenon (Xe) plasma display may be embodiedwithout drastically increasing discharge initiation voltage, thereby,improving light-emitting efficiency.

Table 1 below shows results obtained by comparing PDPs according to thepresent embodiment with a conventional PDP under the same drivingconditions. The light-emitting efficiency may be defined as lightemitting luminance (cd/m²) as an output over consumption power (W) as aninput.

TABLE 1 PDP I According PDP II According Conventional to Present toPresent PDP Embodiment Embodiment Xenon (Xe) content 11% 11% 15% sustaindischarge 202 V 202 V 202 V voltage (Vs) address voltage (Va)  57 V  57V  57 V light-emitting 0.875 0.991 1.127 efficiency (cd/m²W)

Comparing the light-emitting efficiency under the same drivingconditions of the Xenon (Xe) content of 11%, the sustain dischargevoltage of 202 V, and the address voltage of 57 V, the PDP I accordingto the present embodiment may obtain light-emitting efficiency higherthan that of the conventional PDP by about 13.3%. The PDP II accordingto the present embodiment, in which the driving conditions are the sameas those of the PDP I according to present embodiment, except forincreasing the xenon (Xe) content from 11% to 15%, may obtainlight-emitting efficiency higher than that of the PDP I according topresent embodiment by about 13.7%. In comparing the PDPs I and IIaccording to the present embodiment, although the xenon (Xe) content isincreased from 11% to 15%, both PDPs may be driven with the same addressvoltage and sustain discharge voltage because the stepped wall structureis employed, and thereby, a high electric field may be centralizedthereto.

FIG. 5 illustrates an exploded perspective view of a PDP according toanother embodiment. FIG. 6 illustrates a cross-sectional view of the PDPillustrated in FIG. 5, taken along line VI-VI of FIG. 5.

Referring to FIGS. 5 and 6, since the partition wall 124 may beinterposed between the front substrate 110 and the rear substrate 120,the unit cell S may be partitioned. The unit cell S may include the maindischarge space SP, the auxiliary discharge space S1 and the step spaceS2. The auxiliary discharge space S1 may be defined by the steppedpartition wall 124 including the base part 124 a and the projection part124 b. Along with the auxiliary discharge space S1, the step space S2may be prepared on the other side of the projection part 124 b of thepartition wall 124 to symmetrically form the unit cell S. Also, the baseparts 124 a of the partition wall 124 may provide the grooves r suitableto hold the phosphor paste. A phosphor layer 225 may be formed in eachof the grooves r. The groove r at its edges may have substantially thesame height as the base part 124 a of the partition wall 124. In thecurrent embodiment, the phosphor layer 225 may not be formed on thepartition wall 124 interfacing with the auxiliary discharge space S1and, in particular, the phosphor layer 225 may not be formed on the basepart 124 a, which functions as a discharge surface with the scanningelectrode Y. Hereinafter, the PDP according to the current embodiment isdescribed more fully.

The phosphor materials, each including a different material, havedifferent electrical characteristics that may affect a dischargeenvironment. For example, an electric potential of the surface of a Gphosphor material of a zinc silicate system, e.g., Zn₂SiO₄:Mn isnegatively charged, whereas an electric potential of the surfaces of Rand B phosphor materials, e.g., Y(V,P)O₄:Eu or BAM:Eu is positivelycharged. Thus, to eliminate discharge intervention of the phosphormaterials and form a uniform discharge environment, the phosphormaterials may be isolated from an address discharge path by not beingapplied in the auxiliary discharge space S1. If the phosphor materialsare directly exposed to the address discharge path, address voltagesactually applied in the auxiliary discharge spaces S1 may each bedifferent according to the electrical characteristic of the phosphormaterials even though the same address voltage is applied. In otherwords, since the negatively charged G phosphor material may reduce anaddress voltage and the positively charged R and B phosphor materialsmay increase an address voltage, common address voltages actuallyapplied in the auxiliary discharge spaces S1 may each be different, andthus, an address voltage margin may be reduced.

By having the unit cell S spatially partitioned into the main dischargespace SP where display discharge is centralized and the auxiliarydischarge space S1 where address discharge is centralized and having thephosphor materials selectively not being applied in the auxiliarydischarge space S1, an address voltage applied from the outside may notbe distorted based on the electrical characteristics of the phosphormaterials. Therefore, the address voltage may instead be transmittedidentically to all auxiliary discharge spaces S1 so that an addressvoltage margin may drastically be increased. Further, the same dischargeeffect may be obtained even with a low address voltage since morepriming particles may be accumulated when the same address voltage isbeing applied, and discharge intensity may be increased in a displaydischarge. In addition, the phosphor materials may not be applied in theauxiliary discharge space S1 where address discharge is centralized sothat background light by phosphor materials may be removed duringaddress discharging and a high-quality display having high contrast maybe realized.

FIG. 7 illustrates an exploded perspective view of a PDP according toanother embodiment, and FIG. 8 illustrates a cross-sectional view of thePDP illustrated in FIG. 7, taken along line VIII-VIII of FIG. 7.

Referring to FIGS. 7 and 8, since the stepped partition wall 124 isinterposed between the front substrate 110 and the rear substrate 120,the unit cell S may be partitioned. The main discharge space, theauxiliary discharge space S1 adjacent to and connecting to the maindischarge space SP, and the step space S2 may be formed by the steppedpartition wall 124 including the base part 124 a and the projection part124 b. Also, the auxiliary discharge space S1 and the step space S2respectively formed in left and right sides of the partition wall 124may be symmetrical to each other with respect to the main dischargespace SP, and thus, the unit cell S may be formed in a symmetrical form.In particular, in the current embodiment, an electron emission materiallayer 335 may be formed on the top surface of the base part 124 a whichfaces the scanning electrode Y. The electron emission material layer 335may include materials inducing electron emission in response todischarge electrical fields. Examples of the materials inducing electronemission may include MgO nano powder, a Sr—CaO thin film, Carbon powder,Metal powder, MgO paste, ZnO, BN, MIS nano powder, OPS nano powder, ACE,and CEL. The electron emission material layer 335 may provide secondaryelectrons to the auxiliary discharge space S1 in response to a highelectrical field centralized in the auxiliary discharge space S1 so thatdischarge ignition may be facilitated and discharge may be activated.The electron emission material layer 335 may also be provided in thestep space S2 to maximize symmetry within the cell.

FIG. 9 illustrates a cross-sectional view of a modified PDP of FIG. 8.

Referring to FIG. 9, electron emission material layers 435 may beapplied along the interface of the partition wall 124 and the auxiliarydischarge space S1. That is, the electron emission material layers 435may be on side 124 bs of the projection part 124 b and top surface 124as of the base part 124 a, i.e., on auxiliary space S1. Since the highaddress electrical field formed in the auxiliary discharge space S1 isefficiently used and the electron emission material layers 435 areextended along the stepped partition wall 124 interfacing with theauxiliary discharge space S1, electron emission may be reinforced anddischarge may be activated.

FIG. 10 illustrates a cross-sectional view of another modified PDP ofFIG. 8. In the current embodiment, the electron emission material layers435 are not restricted to only in the auxiliary discharge space S1, butmay extend into the main discharge space SP. For example, by anapplication process where an injection nozzle, injecting electronemission materials, is moved from one end of the PDP to the other end ofthe PDP, one electron emission material layers 435 may be formed acrossthe main discharge space SP and the auxiliary discharge space S1. In themain discharge space SP, the phosphor layer 225 may be formed with theelectron emission material layer 435. According to the applicationsequence, the phosphor layer 225 may be formed on the electron emissionmaterial layer 435. The electron emission material layer 435 formed inthe main discharge space SP where display discharge is centralized, mayreact to a discharge electrical field through air gaps (not shown)between the phosphor materials and may emit secondary electrons to themain discharge space SP, thereby activating a display discharge.

FIG. 11 illustrates an exploded perspective view of a PDP according toanother embodiment.

Referring to FIG. 11, the front substrate 110, on which pairs sustainand scanning electrodes X and Y are arranged, and the rear substrate120, on which the address electrodes 122 are arranged, may be disposedto face each other. A partition wall 624 may be interposed between thefront substrate 110 and the rear substrate 120 so that a plurality ofunit cells S is partitioned. Also, the auxiliary discharge spaces S1which are adjacent to and connected to the main discharge spaces SP maybe defined by the stepped partition wall 624 including a base part 624 aand a projection part 624 b.

FIG. 12 illustrates a plan view of the partition wall 624 illustrated inFIG. 11.

Referring to FIG. 12, sides 624 as of the base parts 624 a forming aninterface with the main discharge spaces SP may have a concave formwhich surrounds the center of the cell S. In other words, the sides 624as of the base parts 624 a may not have a simple linear form, but,instead, may have a concave form surrounding the center of the cell S.Since the sides 624 as of the base parts 624 a may be formed in aconcave form and may function as a surface where phosphor materialsadhere thereto, an area where phosphor material are being applied may beincreased, and accordingly, an improvement in light emitting luminancemay be achieved. Also, since the main discharge space SP is defined bythe concave-formed base part 624 a, plasma gas generated as a result ofdischarge may be centralized close to the center and discharge intensitymay be increased.

FIG. 13 illustrates a plan view of a modified partition wall 624 of FIG.12.

Referring to FIG. 13, sides 724 as of base parts 724 a, which form aninterface with the main discharge spaces SP, have a convex formprojecting to the center of the cell S. In other words, the sides 724 asof the base parts 724 a may not have a simple linear form but instead,may have a convex form projecting toward the center of the cell S. Sincethe sides 724 as of the base parts 724 a are formed in a convex form andfunction as a surface in which phosphor materials may adhere, an areawhere phosphor material are being applied may be increased and animprovement in light emitting luminance may be achieved. Further, sincea discharge area of the base parts 724 a which face the scanningelectrodes Y may also be increased, address discharge may befacilitated.

According to embodiments, one or more of the following effects may beachieved.

First, low voltage addressing may be possible and/or a high xenon (Xe)display may be realized so that light-emitting efficiency may remarkablybe increased. Such reduced voltage requirements may be realized inaccordance with embodiments by providing an auxiliary discharge spacebetween scanning electrodes and base parts of partition walls on addresselectrodes. Thus, a discharge path between the scanning electrode andthe address electrode is shortened to be a size of a gap between thebase part and the scanning electrode. Accordingly, since the same amountof priming particles can be generated with lower address voltage,compared with a conventional PDP, driving power consumption may bereduced and/or since more priming particles may be generated with thesame address voltage, light-emitting efficiency can be improved. Thus,according to embodiments in which a high electrical field suitable foraddress discharge is formed in a gap between a base part of a partitionwall and a scanning electrode, priming particles sufficient fordischarge ignition may be secured, allowing a high Xe PDP to be realizedwithout a remarkable increase of discharge initiation voltage. Thus,light-emitting efficiency may be remarkably improved.

Second, symmetric discharge may be induced in a unit cell to provide ahigh-quality display. According to embodiments, an auxiliary dischargespace on a side of the scanning electrode is used to generatecentralized address discharge, while a symmetrical space may be formedon an opposite side of a main discharge space, i.e., on a side of thesustain electrode. Thus, the unit cell may be symmetrical with respectto a center thereof. When the unit cell is symmetrical, displaydischarge may not be biased to any one of the scanning electrode and thesustain electrode, but may have a symmetrical discharge. Also, aconventional asymmetrical luminance distribution in the unit cell may beprevented.

Third, discharge intervention between neighboring cells may beeliminated and reactive power consumption may be reduced. According tothe electrodes arrangement of embodiments, sustain electrodes orscanning electrodes may be arranged such that electrodes of the samekind neighbor each other in adjacent unit cells. Thus, mis-dischargebetween neighboring cells or reactive power consumption wasted through acapacitance formed in a cell boundary may be remarkably reduced.

Exemplary embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation.Accordingly, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made without departingfrom the spirit and scope of the present invention as set forth in thefollowing claims.

1. A plasma display panel (PDP), comprising: a front substrate and arear substrate facing each other; a partition wall interposed betweenthe front substrate and the rear substrate to define a plurality of unitcells, each unit cell including a main discharge space, an auxiliarydischarge space, and a step space, the auxiliary discharge space and thestep space being on opposite sides of the main discharge spaces alongstepped sidewalls of the partition wall; pairs of scanning and sustainelectrodes arranged adjacent the auxiliary discharge spaces and to thestep spaces, respectively; address electrodes extending to cross thescanning electrodes at a location adjacent to the auxiliary dischargespaces; a phosphor layer formed at least in the main discharge spaces;and discharge gas filling the unit cell.
 2. The PDP as claimed in claim1, wherein the auxiliary discharge spaces and the step spaces areconnected to the main discharge spaces and form the unit cells with themain discharge spaces.
 3. The PDP as claimed in claim 2, wherein theauxiliary discharge space and the step space are symmetrical to eachother with respect to the main discharge space.
 4. The PDP as claimed inclaim 1, wherein the sustain electrodes and the scanning electrodes havean electrode arrangement of X-X-Y-Y, the sustain electrodes being X andthe scanning electrodes being Y, so that the sustain electrodes and thescanning electrodes neighbor each other in adjacent cells.
 5. The PDP asclaimed in claim 1, wherein the stepped sidewall of the partition wallincludes a base part and a projection part that projects from a centerof the base part, the base part being wider than the projection part todefine a step form on each side of the projection part.
 6. The PDP asclaimed in claim 5, wherein the width of the base part of the partitionwall is substantially the same as a distance between an outer edge ofone bus electrode to an outer edge of an adjacent bus electrode in anadjacent unit cell, the outer edge of each bus electrode facing awayfrom its corresponding adjacent bus electrode.
 7. The PDP as claimed inclaim 5, wherein the base parts and respective bus lines of the scanningelectrodes at least partially cover each other and are arranged tooverlap each other.
 8. The PDP as claimed in claim 7, wherein the basepart and the bus lines of the scanning electrodes overlap each other atend parts adjacent to the main discharge space.
 9. The PDP as claimed inclaim 5, further comprising an electron emission material layer on a topsurface of the base part in the auxiliary discharge space.
 10. The PDPas claimed in claim 9, wherein the electron emission material layer iscontinuously formed along the top surface of the base part in theauxiliary discharge space and a side of the projection part in theauxiliary discharge space.
 11. The PDP as claimed in claim 9, whereinthe electron emission material layer is formed on the main dischargespace as well as along the top surface of the base part in the auxiliarydischarge space.
 12. The PDP as claimed in claim 5, wherein a side ofthe base part is concave away from the main discharge space.
 13. The PDPas claimed in claim 5, wherein a side of the base part is convex towardthe main discharge space.
 14. The PDP as claimed in claim 5, wherein thephosphor layer is not formed on the top surface of the base partinterfacing with the auxiliary discharge space.
 15. The PDP as claimedin claim 1, wherein the phosphor layer is on the step spaces on one sideof the main discharge spaces.
 16. The PDP as claimed in claim 1, whereinthe phosphor layer is on the step spaces and the auxiliary dischargespaces on both sides of the main discharge spaces.
 17. The PDP asclaimed in claim 16, wherein the phosphor layer is formed to have amaximum thickness in the main discharge spaces,
 18. The PDP as claimedin claim in claim 17, wherein the maximum thickness is substantially thesame as a height of a step in the stepped sidewall of the partitionwall.
 19. The PDP as claimed in claim 1, wherein the discharge gas is ahigh xenon (Xe) gas.